I have been asked over the years if I can produce a larger clear aperture front optic for our Denk Binoviewer/Power Switch Systems. When I first designed the Patented Optical Corrector System (OCS), I decided to use a typical optical blank diameter of 40mm. The clear aperture ended up being 37mm. However, 12 years ago, there were virtually no "commercial mirror makers" creating mirrors of F/4.2, F/4, and now even F/3.5!! Designing and making custom sized optics can be expensive when made in small numbers so I had to decline.

Over the last few years, enough calls have come in where I have decided to take the plunge. We have now produced 30 optical lenses and cells and made them the maximum clear aperture of 45mm. We have to produce a cell of proper gauge of course to house the optic but again, the clear aperture of this OCS Lens is 45mm. We can now ensure that you capture the maximum possible peripheral rays of that steeply converging cone of F/4.5 or faster in your 2" focuser. We test every single optic after mounting and they are performing beautifully. Delivery will be in approximately 30 days.

Order now. go to our website and use the link on the main page for more information!
Russ Lederman/Denkmeier Optical

I hope all of those using our Denk Binos in their dobs become aware of this option. Over the 12 years since I originally designed the OCS Lens, many fast dob users have purchased the Denk bino and Power X Switch with the 2" OCS. This upgraded larger OCS can benefit them. Orders have come in but I think that the "New Product" intro in Astronomy Magazine will help get the word out.-Russ

I hope all of those using our Denk Binos in their dobs become aware of this option. Over the 12 years since I originally designed the OCS Lens, many fast dob users have purchased the Denk bino and Power X Switch with the 2" OCS. This upgraded larger OCS can benefit them. Orders have come in but I think that the "New Product" intro in Astronomy Magazine will help get the word out.
-Russ

George, from the original post: We can now ensure that you capture the maximum possible peripheral rays of that steeply converging cone of F/4.5 or faster in your 2" focuser.

I hope all of those using our Denk Binos in their dobs become aware of this option. Over the 12 years since I originally designed the OCS Lens, many fast dob users have purchased the Denk bino and Power X Switch with the 2" OCS. This upgraded larger OCS can benefit them. Orders have come in but I think that the "New Product" intro in Astronomy Magazine will help get the word out.
-Russ

At WSP, quite a few years ago, Mike Zammit of Star Structure along with Steve Kennedy, a fine fast mirror maker in California and user of our Denk II Binos with both 1.4X and 1.2X OCS* had let me know that the super fast scopes they were using had been shown through ray tracing to have some noticable fall off of illumination with the lower power 1.2X optical lens. Not real bad, but observable.

Basically, to transfer the image plane through the light path of the Denks (this would hold true with any binoviewer), the optical lens must be located rather deeply into the focal plane of the scope, often entering the upper cage a bit. Here's where it gets a bit tricky when deciding whether to use the 1.2X or the 1.4X lenses. The 1.2X requires .75" deeper location than the 1.4X. however, most of you who set out to have a very large and fast dob not only want a short "stepstool-ready" scope, but you want a wide true field of view (TFOV) too. Mike Z. did some on site ray tracing at WSP and determined that going with the 1.4X would be a better option due to the very steep cone in what was an F3.75 mirror, if I remember correctly. remember that it needs to go into the focal plane .75" LESS.

The clear aperture of both the 1.2X and 1.4X OCS lenses were and still are 37mm. The new optic as mentioned is 45mm clear aperture and has the same lower power 1.2X factor.

I was asked if I could make a low power 1.2X with as much clear aperture as possible to negate this clipping. I felt that in a sense, it was not a good option to make 100 optics, especially if the typical blanks that we were already using were 40mm and new tooling, New Cells, retainers, raw material etc. would be required in large numbers. For how many fast dobs? 10? Yikes!

So I sort of declined and had been telling customers with fast dobs that opting for the 37mm 1.2X or 1.4X was a decision they would have to make, weighing the tradeoffs between low power and some falloff/clipping, or less of it with the higher power 1.4X lens.

Well, things being what they are, I am a huge dob fan. I use my own 20" F/f5 with a John Hall mirror (Pegasus) for many years now. But I felt it was finally time to go ahead with this optic since more and more super fast mirrors are showing up and Steve Kennedy felt this would be a very good thing.

My opinion is that ANY dob F/5 or faster should choose this upgrade. F/5 is fast in the telescope world. Typically, large Dobs are expensive and well worth it! So, why not have the largest OCS optic possible in a 2" focuser doing the work? I need a good night to really cross test the 37mm vs the 45mm in my own F/5 but I can say I'd use the 45mm in any case to be sure there is an easily observable gain. I used the 1.2X 37mm in my scope and always had. Now of course, I will use the 45mm! It's here if people want it. Its an honest effort to make an OCS with largest possible clear aperture for a 2" focuser available for those who want one. If I'm trying to grab some photons, I want as many as possible.

*OCS=Optical Corrector System, a term that has been sort of hijacked and used by some others with slight changes. Note that the values of 1.2X and 1.4X are derived via the introduction of the low power optic in the Denk Bino's power switch, used in combination with the large OCS optic. Used alone, these OCS cells would render appx. 2.3X (lower power)vs 2.5X (higher power)in the Denk Binoviewers.-Russ

Ken:The New BINOTRON-27 is completely different from the Denk II or Standard Binoviewer. We worked on this from the ground up. The body is completely made from scratch with new molds. I wanted a thin lightweight ribbed rubber armor for comfort. It's really nice. The prisms are larger at 27mm this.this allows us to improve on a few things:1.We can fixture the prisms when coating and still compeletey cover the 26mm clear aperture now. The old body could not accept 27mm prisms.2.I designed a special proprietary prism baffling and the new larger 27mm prism allows us to do this better, deeper without infringing on the 26mm clear aperture. This means elimination of any out of field reflection from bright objects. It's a big plus3. We are going crazy with polishing and figure every surface to 1/8 minimum wave. Most are 1/10 or better. I have the Zygo data to review.

Please see the website. I have added FAQs and also added more information. It's new,different, with many new features and my Collitron Eyepiece Holders are fantastic, allowing any user to collimate the binoviewer (even indoors with no scope) in minutes or less. It's quick and easy. Honestly, if there was any question as to who in this industry is innovating and not just talking where binoviewers are concerned, I wanted the world to know that we were! I recently introduced the OCS-A45 and now have followed with The Binotron-27. There are real features not seen before in this industry and all of them were on my own wish list because I knew they would benenficial, not just good sounding. Thanks for your continued interest and encouragment! You folks make it all possible and worth it.-Russ